Variable speed transmission



Filed Oct. 2'7. 1937 Pafented der. 1o, 1939 UNITED jsTATr-:s

PA-'rami orales macorporation sppunuon omini zr. 19's?. sei-u1 No. 111,231

The invention relates to variable speed drives of the V-belt type.

The object of the invention is to provide simple and emcient variable speed driving mechanism in which a plurality of V'belts are used.

Other objects of the invention will appear-"from the detail description.

-The invention consists in' the several novel features which are hereinafter set forth and are 10 moreparticularly dened by claims at the conclusion hereof.

-Inthe drawing: Fig. 1 is a side elevation of driving mechanism embodying the invention, the belts being shown in section. Fig. 2 is a plan.

the belts being shown in section. Fig. a is s section on line 3 3 of Fig. 2. Fig. 4 is a vertical section of the pulleys on the counter-shaft, with a low-speed pulley and its drive-belt illustrated in position for low-speed transmission of power.

5 is a similar section illustrating the mecha.- nism in position for high-speed transmission.

The invention is exemplified in variable speed driving mechanism between an electric motor a and a oountershaft b to be driven from the motor for driving any desired machine" or mechanism at two diherent speeds. The motor is supported on a. bracket a' which is secured to a suitable support c. The armature shaft a2 of the motor has secured thereto a plurality of pulleys Iii 'and il, which may be of the same or different diameters and .have V-shaped grooves in their peripheries for respectively driving V-belts i2 and i2.

The m to be drivenby the v-belts and for driving shaft lr comprises a hollow shaft sec- 35 tion h', one end oi which is secured to the counter-shaft b. Shaft section o' is journaled in a hearing i5 carried by the support c and may, if desired, he otherwise additionally supported.

Belts i2, i3 are adapted to drive a pair of seco tional pulleys of diiferent diameters on the counter-shaft for driving the shaft b at two different speeds from the motor o. Each pulley is composed of .a pair of sections having conoidal sidefaces for gripping the sides of the belts, one oi the sections of each pulley being slidable toward or from the other to grip or release the driving belt and control the driving of the counter-shaft and the speed at which it will be driven. Both of the slidable sections are also movable into a neutral position in which neither of the belts is operative to drive the counter-shaft. r

The' pulley which is driven by belt I2 comprises a section it which is held against axial movement on shaft-section b' and a complementary axially movable section It between which s claims. (ci. u-zm the lbelt I3 is connned. The pulley whichnisdriven by belt I2 comprises asection 2'| held against axial movement on shaft section b' and an axially movable section 2'Il between which the belt I2 is confined. The pulley sections II, 21 which are held against axial movementl are supported to rotate around shaft-sectionb' and axially movable pulley sections il* and 21* are slidable on shaft section b' and splined thereto to drive the shaft sections from either pulley.

Pulley-section II is carried I1 around lshailt-section b', is rotatable independently or shaft b, and is connned against enawise movement by a washer Il 'which-is held by bearing ,II and a collar il which is viixedly secured to shaft-section b'. Pulley-section I 6 is provided with 'an inclined or conoldal side-face I6 which is adapted to be engaged by one of the inclined sides of the V-belt I2 and with -an inwardly extending cylindrical hub-portion 22 approximately in the line of the inner face of the V-belt. This hub-portion 22 may be engaged by the inner face \of belt Ii when the latter is loose. The compleinentary` section i6* has an inclined side-face I6 and an integral hub 2l which is slidably mounted 'on shaft-section bf. splines 25 are formed on l shaft-sectlon b' and interilt with grooves in hub 2d to drive the shaft b through said hub and shaft-section b. Pulley-section IIIL is slldable towards pulley-section I8 to cause the inclined side-face of belt I2 to beslillped between the inclined faces i6". I6" of pulley-sections I6, IG', as illustrated in F155. When belt I3 operatively engages the pulley-sections I6,y Ita, the shaft will be driven at high speed through hub 26, splines 25 and shaft-section b. y

'Ehe pulley-section 21 is adapted to be driven by the V-belt I2 and is provided with an inclined side-face 2 for engagement by one side of said belt. A cylindrical portion 29 on section 27 projects axially from the inclined side-face by a roller-hearing toward pulleyesection 21* for guiding the inner fece of the belt when it is loose.A Pulley-section 2l* is ixed by a. screw 3i to the slidable Ihub 24 and is provided with an inclined side-face 21 for engagement with the contiguous inclined side-face ci V-belt I2. The hub of pulley-section 2i is journaled on a roller-bearing 3l around able to alternately render either of the pulleys operative or both inoperative.

The pulley-sections 21* and I6'L are shiftable into an intermediate position, as shown in Fig. 1, in which said sections will be separated from the inner side-faces of the V-belts I2 and I3. In this position, the belts will be lloose on'pulley-sections Il, 21, disengaged from pulley-sections I6l 21, will be guided by the cylindrical portions 22, 29, and free to revolve around shaft-section b' at different speeds. When pulley section 21l is shifted outwardly toward pulley-section 21, the inclined side-faces 21h, 21c of said sections will grip the inclined side-faces of V-belt I2 and cause the low-speed pulley, hub 24, and pulley-section I6* to be driven by said belt. 'I'his will drive shaft b at low speed, as illustrated in Fig. 4.

When pulley-section I6'L is shifted towards pulley-section I6 to grip belt I 3 between inclined side-faces I6, I6, the belt will be operatively connected to drive said pulley-sections and drive, through hub 24 and shaft-section b', the shaft b at low speed. When belt I2 is gripped between pulley-sections 21, 21, beit l: will be loosely guided by the cylindrical portion 22 of section- IG", which may rotate idly. .When belt I3 is gripped between pulley-sections I6, I6, belt I2 will be loosely guided by portion 29 of section 21 which maythen rotate idly. Each of the axially mov- Aable pulley-sections is recessed, as at 54, to receive the cylindrical portion of its complementary section when the sections are brought together to grip the belts.

The mechanism for shifting sleeve 24 to control the operation of the driving mechanism comprises a collar 40 journaled on a ball-bearing 4I which comprises an inner race 42 which is fitted in a groove in hub 24 formed between the hub of pulley-section 21 and a flange on pulley-section IB, and a forked lever 44 which has lugs 45 for engaging and'shifting the collar 40 and is fulcrumed at 46'in a supporting bracket 41. Lever 44 is pivotally ymovable by a collar 4I which is provided with a cam-groove 49 adapted to engage and shift a pin t on the outer end of lever 44. Collar Ilis fixed to a shaft II which is Journaled in a bearing 52 and is adapted` to be rotated by any suitable means to shift lever 44 for setting it to hold the slidable pulley-sections at neutral or for driving at high or low speeds.

The operation will be as follows: To render the driving mechanism idle or inoperative, the operator will rotate shaft 5I to shift lever 44 through cam 49 to separate the pulley-sections I6l and 21, respectively, from pulley-sections I 4 and 21, as illustrated in Fig. l. At such time the belts I3, I2 will be disengaged from pulley-sections I6* and 21, respectively, and the belts will be loosely held on hub-portions 22, 2l of the pulley-sections, respectively. When shaft b is to be driven at high speed, the operator will rotate shaft 5I to shift lever 44 to bring pulley-sections Ii, 21'L into position shown in Fig. 5. Belt Il will then be gripped between pulley-sections I6, I4'l and will drive hub 2.4, shaft-section b and shaft b at high speed. At such time, belt I2 will be supported from pulley-section 21'L and will be guided by and may idly rotate pulley-section 21. When shaft b is to'be driven at low speed, the operator will rotate shaft 5I to shift lever 44 to bring the slidable pulley-sections into position shown in Fig. 4. At such time, belt I2 will be gripped between pulley-sections 21, 21, so the hub 24 will be driven to drive yshall? b.' At such time belt I3 will be guided by the hub-portion 22 of pulley-section I6 and said section may rotate idly with said belt.

The invention exemplifies variable speed drivclaims, without departing from the spirit and scope of the invention.

Having thus described the invention, what 1 claim as new and desire to secure by Letters Patent is:

- l. Variable speed driving mechanism, comprising a plurality of V-belts, a plurality of drivepulleys having grooves therein, fitting the belts, respectively, a shaft to be driven, a pair of pulleys to be driven by the belts, respectively, each comprising a pair of complementary sections having inclined side-faces for gripping the belts, one section of each pair being axially movable on the shaft to engage an inclined side of one of the belts and rotatable with the shaft to drive it, the other section being held against axial movement and rotatable on the shaft, the axially movable sections being fixed to rotate and slide together between the rotatable sections, and means for shifting the axially movable sections to grip either of the belts, respectively.

2. Variable speed driving mechanism, comprising a plurality of V-belts, a, plurality of drivepulleys having grooves therein, fitting the belts, respectively, a shaft to'be driven, a pair of pulleys to be driven by the belts, respectively, each comprising a pair of complementary sections having inclined side-faces for gripping the belts and a cylindrical portion for guiding the inner faces of one of the belts, one section of each pair being axially movable on the shaft to engage an inclined side of one of the belts and rotatable with the shaft to drive it, the other section being held against axial vmovement and rotatable on the shaft, the axially movable sections being fixedly secured together for rotary and longitudinal movement and recessed to receive the cylindrical portions, respectively, and means for shifting the axially movable sections to grip either of the belts, respectively.

3. Variable speed driving mechanism, qomprising a plurality of V-belts, a plurality of drivepulleys having grooves therein, tting the belts, respectively, a shaft to be driven, a pair of pulleys to be driven by the belts, respectively, each cornprising a pair of complementary sections having inclined side-faces for gripping the belts, one section of each pair being axially movable on the shaft to engage an inclined side of one of the belts and rotatable with the shaft to drive it, the other section being held against axial movement and rotatable on the shaft, the axially movable members being iixedly secured together for rotary and longitudinal movement and having hubs, one of which is mounted on and ilxedly secured to the other, and means for shifting the axially movable sections to grip the belts, respectively, comprising a collar between the hubs.

HAROLD G. DAVIS. 

